I found out about the "Plate Solve and Blind Sync" functionality in SGPro. Instead of pointing the scope to a particular star, then centering it and syncing on that star, I could just point the scope somewhere in the sky, SGPro will do a plate solve and use the coordinates for the telescope sync.
Tried it out right away. And it worked "almost". I could see that the sync told the scope the correct direction (I could see in TheSkyX that the scope pointed into the right direction). But when I then tried to slew to a different location, the mount would run the telescope into the pier...
Asked on the mainsequencesoftware mailing list, but couldn't get a good answer :-(
Well, not the end of the world - but it would have been nice to safe an additional 10 minutes of setup time.
I got some more ideas how to make this work!
When my Mach1 mount started to slew erradically, I posted to the ap-gto mailing list. And from that discussion came several ideas how to make this work. Will try this when I'm back home next week!